OCR GCSE Physics A key terms

A material, such as iron, that can be attracted by a magnet and can become magnetised.

One of the two ends of a magnet, called north and south, where its magnetic effects are most noticeable.

The size of a quantity without its direction or sign.

The long, stable stage of a star’s life during which hydrogen nuclei fuse into helium in its core.

An instrument that compares gas pressure with another pressure by using the difference between liquid levels.

A measure of the amount of matter in an object and of its resistance to acceleration, measured in kilograms (kg).

A number equal to the total number of protons and neutrons in a nucleus, written at the upper left of a nuclide symbol.

The sum of a set of measurements divided by the number of measurements.

A material through which a wave travels or with which it interacts.

The curved surface of a liquid in a container. For water in a measuring cylinder, read its lowest point.

The SI unit of speed, meaning the number of metres travelled in one second.

A device that converts variations in sound pressure into a corresponding electrical signal.

A group of two or more atoms joined by chemical bonds.

The turning effect of a force about a pivot, equal to the force multiplied by its perpendicular distance from the pivot.

The turning effect of a force about a pivot, measured in newton metres (N m).

The quantity obtained by multiplying an object's mass by its velocity; it has magnitude and direction.

A naturally occurring satellite of a planet, such as Earth's Moon.

The force produced when the magnetic field around a current-carrying conductor interacts with another magnetic field.

A change in genetic material that can affect how a cell functions or divides.

One billionth of a metre, written as $10^{-9}$ m.

The network of cables and transformers that transfers electrical power from power stations to places where it is used.

A cloud of gas and dust in space from which a star can form.

A temperature-dependent resistor whose resistance decreases as its temperature increases.

The overall electric charge of an object after its positive and negative charges are taken together.

The reduction from the original quantity; it equals the original quantity minus the quantity remaining.

The resistance that would have the same effect on the current from the supply as all the components considered together.

A condition in which upthrust equals weight, so an immersed object has no resultant vertical force.

The mains wire that completes the normal circuit through an appliance.